I have a 20 gallon brackish water set up with the specific gravity of 1.012-1.014 abd ut us 15.5 in tall, 12.5 in wide and 24 in long. i presently have 3 ( all of which are about 0.5 in to 1.25 in long) figure eight puffers in it, but i really want to put something else in with them, i plan on upgrading in about 6-8 months so out growing the tank won't be much of a problem. I really kind of want some gobys, the LFS said that knight gobys can get along well with them but i am not so sure, any help is appreciated.